The genus Candida Berkhout

The properties of 53 fermentation type II strains of the genusCandida Berkhout were studied. The strains in question were originally identified asCandida tropicalis (Castellani) Berkhout,Candida pelliculosa Redaelli,Candida robusta Diddens et Lodder,Candida intermedia (Cif. et Ashf.) Langeron et Guerra,Candida langeroni Dietrichson,Candida obtusa (Dietrichson) v. Uden et Carmo Sousa and as various intermediate forms between these and other similar species. The classification criteria were extended by a number of very important characteristics, such as the degree of utilization of raffinose, the assimilation of lysine, xylose, cellobiose, maltotriose, maltotetraose and arabinose, virulence for mice, nutrient requirements, serological properties, etc. Actual classification was based on the numerical method of a similarity count. On the basis of this extension of the classification criteria, the characteristics of the speciesCandida tropicalis (Castellani) Berkhout andCandida pelliculosa Redaelli were defined in greater detail.Candida intermedia, evaluated on the basis of previously employed characteristics (lactose utilization, non-assimilation of KNO₃) does not appear to be a separate species, but a collection of different border-line forms of other species of this group.Candida robusta Diddens et Lodder is regarded as a member of the genusSaccharomyces, notCandida. The varietiesCandida tropicalis var.lambica andCandida pelliculosa var.cylindrica likewise do not seem to belong to the species concerned and will have to be studied in greater detail from the genetic aspect, in relation to other membrane-forming types ofCandida. The authors' extension of the classification criteria considerably reduced intraspecific variability, particularly in the speciesCandida tropicalis (Castellani) Berkhout, and led to greater accuracy in the practical diagnosis of this species, which is frequent in clinical material.